AI Core with head-sink to big for the UP Core

I Just received my order UP Core, UP Core carrier and a UP AI Core. But the I core has a heat-sink on and the small extension board for the IO Pins is to broad and to less high mount everything. Is it save to run the AI Core without the head-sink? Are there other head-sinks.
Have a look at the images attached.
So how to I use the AI Core with the UP Core?